1. Field of the Invention
The present invention relates to a hand tool and, more particularly, to a socket assembly for operating nuts of three different sizes.
2. Description of the Related Art
A nut has successive sizes of 9 mm, 11 mm, 13 mm, 15 mm, 17 mm, 19 mm, 21 mm, 23 mm and the like. A conventional socket assembly in accordance with the prior art shown in FIGS. 16-19 is used to operate the nut and comprises an outer socket 6, an intermediate socket 7 and an inner socket 8. The outer socket 6 has a first end provided with a tool connector 61 and a second end provided with a workpiece connector 62. The workpiece connector 62 has an interior provided with a receiving chamber 63. The receiving chamber 63 has a periphery provided with a first inner ratchet portion 64. The outer socket 6 has a periphery provided with a screw bore 65 connected to the receiving chamber 63. The intermediate socket 7 has an outer wall provided with a first outer ratchet portion 71 engaging the first inner ratchet portion 64 of the outer socket 6 and an inner wall provided with a second inner ratchet portion 72. The intermediate socket 7 has a periphery provided with an elongate slot 73 having a front end 731 and a rear end 732. A first elastic member 74 is mounted in the receiving chamber 63 of the outer socket 6 and biased between the intermediate socket 7 and the outer socket 6. The inner socket 8 has an outer wall provided with a second outer ratchet portion 81 engaging the second inner ratchet portion 72 of the intermediate socket 7 and an inner wall provided with a third inner ratchet portion 82. The inner socket 8 has a periphery provided with a through hole 83. A second elastic member 85 is mounted in the receiving chamber 63 of the outer socket 6 and biased between the inner socket 8 and the outer socket 6. A first limit member 75 is screwed through the screw bore 65 of the outer socket 6 and received in the rear end 732 of the elongate slot 73. A second limit member 84 extends through the through hole 83 of the inner socket 8 and is received in the front end 731 of the elongate slot 73.
In operation, referring to FIG. 20 with reference to FIGS. 16-19, the conventional socket assembly is used to mount and operate a nut 9 with a smaller size which is smaller than that of the third inner ratchet portion 82 of the inner socket 8. The tool connector 61 is driven by a motorized or hand tool. The third inner ratchet portion 82 of the inner socket 8 engages the nut 9, the second outer ratchet portion 81 of the inner socket 8 engages the second inner ratchet portion 72 of the intermediate socket 7, and the first outer ratchet portion 71 of the intermediate socket 7 engages the first inner ratchet portion 64 of the outer socket 6, so that when the outer socket 6 is rotated, the intermediate socket 7 is rotated to drive the inner socket 8 which is rotated to drive the nut 9 so as to lock or unlock the nut 9.
Referring to FIG. 21 with reference to FIGS. 16-19, the conventional socket assembly is used to mount and operate a nut 91 with a mediate size which is greater than that of the third inner ratchet portion 82 of the inner socket 8. When the nut 91 is inserted into the intermediate socket 7, the inner socket 8 is pushed by the nut 91 toward the receiving chamber 63 of the outer socket 6. At this time, the second limit member 84 is moved in the elongate slot 73. The second inner ratchet portion 72 of the intermediate socket 7 engages the nut 91, and the first outer ratchet portion 71 of the intermediate socket 7 engages the first inner ratchet portion 64 of the outer socket 6, so that when the outer socket 6 is rotated, the intermediate socket 7 is rotated to drive the nut 91 so as to lock or unlock the nut 91. When the nut 91 is removed from the intermediate socket 7, the inner socket 8 is pushed outward by the second elastic member 85, and the second limit member 84 is moved in the elongate slot 73 to abut the front end 731 of the elongate slot 73.
Referring to FIG. 22 with reference to FIGS. 16-19, the conventional socket assembly is used to mount and operate a nut 92 with a larger size which is greater than that of the second inner ratchet portion 72 of the intermediate socket 7. When the nut 92 is inserted into the outer socket 6, the intermediate socket 7 is pushed by the nut 92 toward the receiving chamber 63 of the outer socket 6. At this time, the first limit member 75 is limited in the elongate slot 73. The first inner ratchet portion 64 of the outer socket 6 engages the nut 92 so that the outer socket 6 is rotated to directly drive the nut 92 so as to lock or unlock the nut 92. When the nut 92 is removed from the outer socket 6, the intermediate socket 7 is pushed outward by the first elastic member 74, and the elongate slot 73 is moved on the first limit member 75 until the rear end 732 of the elongate slot 73 abuts the first limit member 75.
Therefore, the conventional socket assembly is used to operate nuts 9, 91 and 92 of three different sizes. However, the torque from the nut is entirely tolerated by the intermediate socket 7 and the outer socket 6, so that each of the intermediate socket 7 and the outer socket 6 needs to have a determined thickness which is greater than 1 mm, such that the inner diameter of each of the second inner ratchet portion 72 of the intermediate socket 7 and the first inner ratchet portion 64 of the outer socket 6 has to be shortened by more than 2 mm. Thus, the conventional socket assembly is only available for operating three discontinuous sizes of nuts 9, 91 and 92, such as 13 mm, 17 mm, and 21 mm, or 15 mm, 19 mm and 23 mm or the like, and cannot be used to operate three discontinuous sizes of nuts 9, 91 and 92, such as 17 mm, 19 mm and 21 mm, or 19 mm, 21 mm and 23 mm or the like, thereby limiting the versatility of the conventional socket assembly.